Tissue-specific resident cells have been identified as a promising population of progenitor cells for cell-based therapies. We describe here the isolation from adult human hearts of tissue nonspecific alkaline phosphatase-positive cells (ALPL+ cells) with mesenchymal stem cell (MSC) characteristics. Samples from 24 adult cadaveric donors were obtained from a valve bank. Mean total ischemia time was 21.5 ± 9.1 hours. The success rate for the isolation of human heart-derived cells by the explant

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... ulture technique was 70% for the right auricle (14 of 20 trials) and 33% for the right ventricle (7 of 21 trials). The total auricle-derived cell population (TAD) was used for the purification of ALPL+ cells. TAD and ALPL+ cells expressed markers for MSC and pericytes. TAD cells and ALPL+ cells differentiated into adipocytes, osteoblasts and chondroblasts, and ALPL+ cells expressed markers of these three lineages more strongly than TAD cells, as shown by RT-PCR. This population therefore has a greater potential for differentiation into mesechymal lineages than TAD cells. Both cell populations express some markers of cardiac progenitors, such as GATA4, CD117 and VEGF. ALPL+ cells expressed troponin T and ABCG2, which are also markers of the cardiac lineage. Heart samples from tissue banks could be considered as sources of MSC with putative commitment towards cardiac lineages, even after prolonged ischemia times.